OBJECTIVE: The aim of this work is to analyze the myocardial flow direction of patients submitted to transmyocardial laser revascularization (TMLR), using the first - pass magnetic resonance imaging (MRI). METHODS: Ten patients submitted to TMLR with CO2 laser (potency of 800 W) were studied with magnetic resonance imaging (MRI) of fast gradient -- eco- EPI hybrid sequence used in a 1.5 TGE CV/i scanner (Sigma CVMR - General Eletric -- Milwaukee-USA) to evaluate myocardial perfusion. Bolus of Gadolinium -- DTPA (0.1mmol/Kg) was injected by a peripherical intra-venous line at 5 ml/sec at rest and during peak stress of dypiridamole. The distribution of the contrast through the myocardial regions was analyzed. RESULTS: After a mean follow-up of 14.7 months, 6 (60%) patients showed significant myocardial ischemia at least in one of the left ventricular walls. The blood flow was inverted, from subendocardium to subepicardium, just in 1 (10%) patient. CONCLUSIONS: First-pass MRI is an efficient method to show the direction of the myocardial blood flow. In one of the studied patients, the inverted myocardial blood flow (from the endocardium to the epicardium), suggested the patency of the channels created by TMLR.
Myocardial revascularization; Laser surgery; Magnetic resonance spectroscopy
